Telephone-exchange system



June 1925- 1,540,064

c. B. FOWLER TELEPHONE EXCHANGE SYSTEM Filed Sept. 16, 1920 Marq/nd/ byof m 4295/. v

Patented June 2, 1925.

en res PATENT I CLA'RENC-E B. -F-OWLER',=OFPNEWYOZRK, N. Y.,. ASSI G'NiORT- WESTERN" .ELEET-RIG 00M BANsY, INCORPORATED, OFNEW? YEGRK, NI ArGORHQRA'JJIQ'N- GF 11 133) Y'ORK..

FrEL rHonn-nxcnrmen sys'rnm.

Application filed September '16, 1920. Seria1No. 4 10,592;.

T 0 all whom itwnaiy come m Beit known that I, Cmnnnoe B. FOWLER, a citizen of :the UnitedStates, residing in New York city; in the county of New York and State of New Yorl t, "have" invented certain new and useful Improvements in Telephone-Exchange Systems, .of which the following is a full, clear, concise, and exact description. i

This invention relates to telephone exchange systems, and more particularly to such systems in which. connections'bet-ween telephone. lines' terminating at manual and automatic exchanges, are establishedby way of trunk circuits,v over which v automatic.

switches at the automatlc exchange .are

actuated under the control: of an. impulse sender at the manual exchange to effect" connections" between subs'criber-s of the man"- ual exchange andsnhscribers of. theautoinatic exchange. A

The object. of this invention is the production of an improved. system of this naturewherein the work" ofl the operator at the manual exchange is reduced" to a minimum so that connections between subscribers of themanual andtlie automaticexchange may beestabli'shed rapidly and e'liiciently. I

One feature of the invention consists in the provision of means whereby the simple insertion of the calling plug of a cord circuit into the 'jack of, a trunk circuit, places the impulse sender in operative re lationship with the trunk circuit and causes the trunk circuit to be. extended to an idle one of a. plurality of trunks extending to the automatic exchange.

Another feature of the' invention consists in the provision of a signal" in a system of this character, to indicate to the operator atthe manual exchange when the connection is in condition for tlies'ending. of' impulsesh Still another feature of the invention consists in the provision o'fmea ns,whereby, when the signalisactuated. indicating'that the trunk, towhich the'calling plug of" the cord circuit; has been connected, is. in corn dition for the sending of" impulses and the sender has been operated, it is impossible to (lisassociate the impulse sender from that trunk until the impulse sender has'del-ivered the impulses;

irnotherfeature of the inventionconsists in theprovision of means in a. system of this nature, wherein-the-siinple, insertion of" the calling plug of tlie- COTClClTCLllU into the jack of the-trunk circuit not only: serves to associate tlie'i-mpulse sender with the trunk circuit, and-toextend. the trunk cir illustrates one embodiment of the invention.

There is shown in the drawing,'. one of av plurality oftrunk lines T which tel-mi nates at an operators position" at the man'- ual exchange in a-jack 21. Associatedwith the other end of the trunk circuit T isa non-numerical switchalso located at the manual exchange. Accessibleto the nonnulnerical switch N. are a number off trunk lines leading I to numerical or 1 d'irectively controlled switches, such as. selector o1 connector switches, at the automatic exchange. -These switches being of a wellknowirtyrm; it .is not thought necessary to illustrate them in the drawing-L The trunk circuit '1 is normally" divided" into inner and outer sections, said sections being in- 28 and 29;. Associated with the outer seeso cuit to anidle interoffice 'tru'nlexbut also.

tion' of the trunk circuit T is a. polarized;-

relay 25, which controlsare1ay26 associated" with the inner section of the trunk. which in turn controlsthe supervisory relay .11 of' the. cord circuit B; A slow-to-relea-se relay 23' is energized" aperiod; suflicient'ly long after the plug of the cord circuit B is inserted into the jack 21 of the trunk circuit T,.to"ca-use thetripping of the machine ringing at the cord circuit B;

The manual station A may be of any suitable type of common battery station. At the manual exchange, the line of the station A. is provided with a line-jack 3, a

for automatic connection and disconnection of the operators telephone set and for automatic ringing.

The impulse sender S common to. the trunk circuits, such as T, at the operators position, is provided with interrupting contacts 61 and with oft-normal contacts 60. Upon the initial movement of the sender S from normal position, contacts 60 are closed and remain closed until the sender S returns to normal position. As the sender returns to normal position, contacts 61 are interrupted. For connecting the impulse sender S with the trunk line, there is provided for each operators position, an automatic switching mechanism, which is shown above the dotted line in the drawing together with the impulse sender S. This switching mechanism may be of any well-known type of step-bystep switch and the particular mechanism herein disclosed comprises three brushes 50, 51 and 52, which are adapted to be moved under control of the stepping magnet 45 over the contact banks D, E and F respectively. A pilot lamp 53 indicates to the operator when the impulse sender S is connected in operative relationship with a trunk circuit.

The nature of the invention is such that it is believed aclear understanding thereof will be obtained from a description of the operation of the system shown in the drawing..

Let it be assumed that station Aoriginates a call, lighting the line signal 2 in the usual manner in response to the operation of the line relay 1. The operator in answering the call, inserts plug 5 of the cord circuit B intofjack 3 thereby disconnecting the line relay 1 and extinguishing the line signal 2 due to the operation of cut-off relay 4 of the line circuit which operates in series with relay 6 of the cord circuit over a path extending from ground, winding of relay 4, sleeves of ack 3 and plug 5, left and middle windings ofrelay 6 in series, left-hand normal contactsof relay 9, resistance 12, front contact and armature of supervisory relay 7, which is operated when plug 5 is inserted into jack 3, to grounded battery. Supervisor-y relay 7 is operated when plug 5 is inserted into jack 3 over a path extending from ground, upper left-hand winding of repeating coil 10, tips of plug'5 and jackB through the loop of station A, rings of jack 3 and plug 5, winding of supervisory relay 7 and lower left-hand Winding of repeating coil 10 to grounded battery. Due to the energization of supervisory relay 7 supervisory lamp 8 is prevented from lighting. Relay 6 in operating connects the .operators telephone set (not'shown) to the cord circuit B and the operator may inquire the wants of the calling subscriber. Assuming that the calling subscriber desires connection with a line at the automatic exchange, the operator inserts calling plug 20 of the. cord circuit B into jack 21 of the trunk circuitT, whereupon slow-ton-ele-ase relay 24 of the trunk circuit T is energized over a path extending from ground winding of relay 24, inner righthand armature and back contact of relay 22, rings of jack 21 and plug 20, lower normal contacts of relay 18, Winding of supervisory relay 11, and lower right-hand Winding of repeating coil 10 to grounded battery. Starting the operation of relays in the trunk circuit from the ring side is done in order to prevent a possibility of a false impulse being sent to the switch at the automatic exchange due to making and breaking the sleeve circuit while inserting the plug 20 into the ack 21. Relay 24 in attracting its left-hand armature removes ground from terminal of the contact bank E. Relay 24 in operating also completes a circuit for relay 23 and motor magnet 45 over a path extending from grounded battery front contact and outer right-hand armature of relay 24 and thencein parallel, one path extending through the Winding of relay 23 and back contact and left-hand armature of relay 22 to ground and the other through the righthand armature and back contact of relay 27 right-hand armature and back contact of relay 43, resistances 7 5, winding armature and back contact of magnet 45 and brush 51 to ground. All the terminals of the bank E, to which no trunks are connected are strapped to ground. Relay 23 thereupon operates and completes a circuit for relay 9 of the cord circuit B and relay 22 of the trunk circuit T over a path extending from ground, front contact and left-hand armature of relay 23, winding of relay 22, sleeves of jack 21 and plug 20, winding of relay 9 and lamp 14 to grounded battery.

Supervisory lamp 14 thereupon lights, indicating to the operator that the connection is progressing. Relay 9 operates and at its left-hand contacts disconnects the left-hand and middle windings of relay 6 from series aiding relationship and connects the lefthand and right-hand windings in series opposing relationship thereby causing the de energization of said relay 6 resulting in the disconnection of the operators telephone set from the cord circuit B. Relay 9 inoperating, also completes a circuit for relay 18 over iii means-a ture and backcontact ofrelay 15, baclr con tact and armature of relay 17,-and'windi'ng of relay 18 to grounded battery. 'It'willbe noted, that the parallel path for current through the winding of relay 17 to relay 18, is short-circuited by the direct path through the armature and bZLClC- COWERCt of relay thus preventing relay 17 from energizing at this time. Relay 18in operating conne'cts ringing current from a source 16 through the winding of'relay 15 to the cord circuit at the alternate contacts of relay 18.- Th-is ringing current is immediately tripped, however, due to battery being connected to the ring of the cord circuit, when slow-to-release relay 23 of the trunk circuit T, operated over a patl'i extending from grounded battery, outer right-hand armature and front contact of relay 23, rings of jack 21 and plug 20, lower alternate contacts of relay 18 and winding of relay 15 to source of ringing current 16; Relay 15 is thereupon energized and in :iitt "acting its armature removes the short circuit from relay 17 thereby connectlng said relay 17 in series wlth relay 18. Relay 17 1s thereupon energized and locks up under control of relay 9,

Relay 18'is thereby short-circuited and retracts its armatures thus disconnecting the ringing current and renderii'rg the talking conductors of the cord circuit B continuous. It is thus seen that ringing current is immediately automatically tripped when the plug 20 is inserted into the jack21.

When relay 22 of the trunk circuit T en ergizes, a locking circuit therefor is closed through lts fron-tcontacts and left-handar mature to ground. Relay 22 111 operating opens the circuit for relay 23' causing the deenergization of this relay. Relay 23 being of the slow-to-releasetype maintains battery upon the ring of the trunk circuit T' sufficiently long to cause the tripping oi the ringing current. It will be noted that when relay 23 energized it also connected ground to the tip conductor 78 of the trunk circuit T, said ground being utilized for tripping machine ringing when party line ringing is employed, at cord circuit B. Relay 22 m operatingalso opens the originalenergizing.

gages terminal 70 from which ground was removed when relay 24c energized, whensa id brushes come to rest. Relay 27 then operates over a path extending from ground, left-hand armature and back contact of rehand armature otrel a y 24 to ground.

lay4 3, back contact and-aanatu're of relay 4A, pilot lainp'tti, brush 5 2, terminal '71, ar mature andjba'ck con-taetof relay 26, righthand winding of relay 27, and outer righthand armature and front contact of relay 2-1-3 to groun'd edba'ttery. Due to the resistarce of the right-hand windingof relay 2?, lamp 53 does not obtain sulticient current to lightinthis circuit. Relay 27, in operating, locks up over a-- p'asth'extending from grorunhulv battery, frontcontact and outer right-hand armature of relay 24, left-hand wincliugof relay 27, left-handarmature and front COl b tact of relay 2-? and front contact andleft- Relay 27 in operating disconnectsbattery from stepping magnet and their connects ground through the left-hand contacts of re;- l-ays 24: and 27 to terminal 70, thus renderi" said terminal busy to other: switches while the connection exists. It will be notedthat it the brush 51 had been resting'on' terminal 70, when plug. 20 was inserted intojack 21,-; ground would have been removed from terminal 7 0' as soon as relay operated so that the steppingnmgiret would ha e notoperate'd. Ter1ninal 70 would have been rendered busy as soon asrelay 27' operated.

At the same time that thebrushes 51 and 52 were being moved to associatethe impulse sender S'with' the trunk circuit '1,

llll

brushes 40, 11* and 42of the switch N were being. moved to extend the trunk 'T to anidle succeeding. switch. Assuming: that, when plug2t) inserted into'ja'ck 21, brush 42,- of' the switch N is resting. on a busy 7 or grounded terminal 95, thisgroundcauses energization of stepping magnet 32" of the switch N over a path extending from grounded battery, winding, armature and back contact: of magnet 32, front contact and outerrigl1tl1and armature of relay 22, lower inner normalcontacts of relay 31, anct brush 4:2 to grounded terminal 95. Magnet 32 thereupon attracts its armature and moves thebrushes 40, 11 and-4 a and switch N in a manner trellhnown. "Relay 31 does not operate at this time due to the direct path to" ground at the terminal 'of the switch N for battery through the winding of magnet 32; Under the control of steppi'ng'magnet 32, the brushes 40, 4:1 and e2 of the switch N are moved step-byelep until the ungrounded terminal of an idle succeeding switch is reached, whereupon relay- 31 operates over a path ez'rte'nding from grounded battery, winding; armature and back contact of magnet 32, front contact and outer right-hand armature of relay 22 and winding of'rela y 31 to ground- Dne to the high resistance of the windingof relay 31, magnet 32 will not operate in series therewith. Relay 31 in operating connects ground t'l'irough its lower inner alternate contacts to the. selected terminal to render Cir such terminal busy and'eXtends the talking conductors of the calling linethrough to the succeeding switch through its upper and lower intermediate cont-acts. As soon as relay 31 operates, pilot lamp 53 lights, indicating to the operator that the circuit is in condition for dialing, over a path extending from ground, left-hand arn'iature and back contact of relay 43, back contact and armature of relay Pl, lamp 523, brush 5L, terminal 71, armature and front contact of relay 26, lowermost armature and front contact of relay 31, front contact and righthand arn'iature of relay 27, and outer righthand armature and front contact of relay 2a to grounded battery.

Upon receiving this signal the-operator may actuate the impulse sender S in accordance with the number desired by the calling subscriber. Upon the initial movement of the sender. S, ofl'normal contacts are closed thereby operating relays 43 and 30 over a path extending from ground through contacts 60 of sender S, winding of relay l5, brush 50, terminal 72, winding of relay 30 and outer right-hand armature and front contact of relay 2 f to grounded battery. Relay 4:3 in attracting its left-hand armature removes the short-circuit around relay 44, causing the operation of said relay 4 1-.

Relay 44 in operating removes the direct.

path to ground through pilot lamp and causes said lamp to be extinguished due to the high-resistance of the winding of relay l4. Relay 43 in operating also opens the operatingrcircuit of stepping magnet 45 so as to prevent its operation until the dial restores to normal position. This is done to prevent premature stepping of the position switch should the operator plug into another jack after the movement of the dial and before the dial is restored to normal. It is thus impossible to associate the sender with a second trunk circuit should the on eratorv plug into a second trunk before the sender has delivered all the impulses.

Relay 30 in operating opens the talking conductors of the trunk circuit T and connects the interrupting contacts 61 ofthe sender S thereto. As the impulse sender S returns to normal position, the contacts 61 are intermittently opened in accordance with the digits dialed by the operator to cause the setting of switches at the automatic exchange in a manner well-known in' the art.

hen impulse sender S' returns to normal position, relay 3O releases thereby rendering the talking conductors of the trunk circuit continuous, disconnecting the impulse sender S from the talking conductors and substituting therefor the bridge of the polarized relay 25. The sender S is then free for use with another trunk circuit.v 7 he polarized relay does not operate at this'time since the direction of flow of current through its path winding is not in the proper direction to lVhen the called subscriber responds, a

current reversing relay may be energized at the automatic exchange.

The energizing of this relay may reverse the battery connections with the talking conductors of the trunk circuit whereby polarized relay 25 bridged across the talking conductors of the trunk circuit T, is energized and closes its contacts. Relay in energizing bridges relay 26 across the inner section of the trunk circuit T over a extending from tip conductor 78 through the winding of relay 26, front contact and armature of relay 25 to ring conductor 79. Due to the bridge across the inner section of the trunk circuit T, supervisory relay 11 of the calling end of the cord circuit will be energized thereby causing the extinguishing of supervisory relay let, which indicates to the ope 'ator that the called suhscriber has responded.

At the conclusion of conversation the subscribers restore their receivers to the switchhooks. The restoration of the receiver to the switchhook at the station A causes the deencrgization of relay 7 and the lighting relay 11 deenergizes permitting the lighting of the supervisory lamp let which indicates to the operator that the called subscriber has restored the receiver to the switchhook. The

operator may thereupon disconnect the plug 5 from the jack 3 and the plug 20 from the jack 21, whereupon all apparatus associated with the cord and trunk circuits except the brushes 50, 51 and 52 will be restored to.

normal position. hen the loop across the outer section of the trunk circuit T is in- .terrupted the switches at the automatic ex change will be restored to normalin the well-known manner.

What is claimed is:

1. In a telephone exchange system. a calling line, a cord circuit, an operators telephone set,means for automatically connecting said set with said cord circuit when said cord circuit is connected to said calling line, a plurality of trunk circuits, a non-numerical switch for each of said trunk circuits, nu merical switches accessible to each of said nseam alien-nume cal sw tch s, an iian lse s d Ilene-ally in i pe at ve -1=e1ati ns ip -witl1 sa dtrunk. ,erreuita and means responsive to the connection of said cord c rcuitw tl .one

of said ttr ank circuits 0 gtlisconnecting ,said

mpulse se d a ward wmreu t erm n t ng in an answering and-a cal i g -n ng,- a tepyep sw tc fo plac ng, s id misus de n pos t ng t z et cenn c ed ,wit any one of said trauik lines means responsive to 1- i the insertion of the callingaplug ofthe cord ci cuit; in th jac of: neth tru in te op rat ng s id witc aand mean ne ativeavhen the sw tch is. set and thesender ;l S actuated ;f 1-- connecting it; directly-to ,the

selected truukl ine. a I

3. In a telephone system, a plurality of trunk L nes, avne q nmeri a n ch-fe leach trunk-line,,aninipu es mle c mmen t said trunk lines, a cord circuit, and means responsive to the connection of said cord circuit withangidle tnuuk'line and to the actuation of the sender for placing saidsender in exclusive operative relationship with said trunk line and for causing said non-numerical switch to operate to extend said trunk.

4:. In a telephone system, a plurality of trunk circuits, an automatic switch common to said trunk circuits, an impulse sender, a cord circuit, means responsive to the connection of said cord circuit with one of said trunk circuits for causing said switch to operate to place said sender in connective relationship with said trunk circuit and means efi'ective when the sender is actuated for connecting it directly to the seized trunk circuit.

5. In a telephone system, a plurality of trunk lines terminating in jacks, a step-bystep device, an impulse sender, a cord circuit terminating in an answering and calling plug, means actuated when the calling plug tuated for connecting the sender directly to the selected trunk line.

6. In a telephone system, a plurality of trunk lines terminating in jacks, a step-bystep device, a cord circuit terminating in an answering and calling plug, an impulse sender, a signal, means actuated, when the calling plug of said cord CIlICUlt is inserted into the jack of one of said trunk lines, for

operating said step-loy-step device to place said sender 1n connective relationship w th said trunl; line,means effective through said stepsb wstepj device when, the impulse sender ,is actuated for connecting itdli'ectly' to the selected trunk line, and means to actuate and maintain said signal actuated untilthe impulse sender has heenoperated.

7. In autelephone system, a pluralitytof trunk circuits eachiterminating in ,a'jack, an 1mpulsesender, a cord circuit terminating n ananswering and calling plug and equipped with. machine. ringing, and means operated, Whenthe callingplug of the cord 'cjircuitis inserted into-thej ack of one of the trunk circuits, for tripping the machinefringing and for connecting the impulse sender with the ,trunk circuit. I

8. In a telephone system, a calling line, a ,cord circuit terminating ,in an vanswering andcalling plug,,a tnunlz circuit terminating in a jack, an impulse sender, anoperators telephone set, asource vof machine ringing Y'assoc ated with said cord .clrcult,v means respons ve totheconnection of the answer ng plug. of the cord circuit with the callingline for connecting the. operators telephone set in operative relationship with the calling l ne, an mean spon v t the a ctie of the call ng plug ofthe'cordgcincuit with the jaclr of the trunk circuit for disconnect ing said operators telephone set from the cord circuit, for tripping said machine ringing, and for placing the impulse sender in operative relationship with said trunk circuit. Y

,9. In a telephone system, a plurality of trunk circuits, numerical switches accessible c to each of'said trunk circuits, a cord circuit, an impulse sender common to said trunk circuits, a pair of step-by-step switches, and means responsive to the connectionof said cord circuit with one of said trunk circuits for operating one of said step-hy-step switches to connect the impulse sender with the trunk circuit and for operating the other of said switches to extend the trunk circuit to an idle numerical switch.

10. In a telephone system, an operatorsposition, a plurality of trunk lines terminatmg thereat, a non-numerical switch for each of said trunk lines, an impulse sender common to and normally disconnected from said trunk lines, cord circuits at said opercircuits, a step-by-step mechanism actuated when one of said cord circuits 1s connected one of said cord circuits is connected to one of said trunk circuits for associating the sender with the connected trunk circuit,

to one of said trunk circuits for rendering the sender individual to the trunk circuit taken for use, means GIIGCUVG when the sender is actuated for connecting it di-' rectly to the seized trunk circuit and means for excluding the sender for use with'other trunk circuits until the sender has operated to deliver the impulses.

13. In a telephone system, a plurality of trunk circuits, a plurality of switches one for each of said trunk circuits, an impulse sender, an automatic switch common to SiLlCl' trunk clrcuits, a cord circuit, and means re-' sponsive to the connection of the cord circuit with one of the trunk circuits vfor operating the switch common to the trunk cir- 7 cuits for connecting the sender to the trunk circuit taken for use andv for operating the switch'individual to the trunkcircuit to extend the trunk. v e

14. In a telephone system, a plurality of cord circuits, a plurality of trunk circuits, an impulse sender common to said'trunltcircuits, an automatic switch actuated when one of said cord circuits is connected to one of said trunk circuits for rendering the sender individual to the trunk circuit taken for use, and'means for connecting the sender directly to the selected trunk circuit when the sender is actuated and for excluding it for use with other trunk circuits until the sender has delivered the impulses corre- 'sponding to the setting of the sender.

'15. In a telephone system, a" trunk circuit, an impulse sender, a link circuit equipped for machine ringing, and means responsive to the connection of the link circuit with the trunk circuit for tripping the machine ringing and forplacing the impulse sender in operative relationship with the trunk circuit. V p

In witness whereof, I hereuntosubscribe my name this 13th day of September A. D., 1920.

CLARENCE "B. FOWLER. 

